Problem: Khan.scratchpad.disable(); To move up to the maestro level in his piano school, Michael needs to master at least $123$ songs. Michael has already mastered $18$ songs. If Michael can master $2$ songs per month, what is the minimum number of months it will take him to move to the maestro level?
Explanation: To solve this, let's set up an expression to show how many songs Michael will have mastered after each month. Number of songs mastered $=$ $ $ Months at school $\times$ Songs mastered per month $+$ Songs already mastered Since Michael Needs to have at least $123$ songs mastered to move to maestro level, we can set up an inequality to find the number of months needed. Number of songs mastered $\geq 123$ Months at school $\times$ Songs mastered per month $ +$ Songs already mastered $\geq 123$ We are solving for the months spent at school, so let the number of months be represented by the variable $x$ We can now plug in: $x \cdot 2 + 18 \geq 123$ $ x \cdot 2 \geq 123 - 18 $ $ x \cdot 2 \geq 105 $ $x \geq \dfrac{105}{2} \approx 52.50$ Since we only care about whole months that Michael has spent working, we round $52.50$ up to $53$ Michael must work for at least 53 months.